Improve LayoutHelper usage

kizitonwose · Jan 15, 2025 · 12a256b · 12a256b
1 parent aea1992
commit 12a256b
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Showing 5 changed files with 13 additions and 14 deletions.
diff --git a/view/src/main/java/com/kizitonwose/calendar/view/CalendarView.kt b/view/src/main/java/com/kizitonwose/calendar/view/CalendarView.kt
@@ -184,7 +184,7 @@ public open class CalendarView : RecyclerView {
         }
 
     /**
-     * Interface with methods that can be overridden
+     * Helper class with methods that can be overridden
      * in the internal layout manager.
      */
     public var layoutHelper: LayoutHelper? = null

diff --git a/view/src/main/java/com/kizitonwose/calendar/view/LayoutHelper.kt b/view/src/main/java/com/kizitonwose/calendar/view/LayoutHelper.kt
@@ -5,10 +5,13 @@ import androidx.recyclerview.widget.RecyclerView
 import com.kizitonwose.calendar.view.internal.CalendarLayoutManager
 
 /**
- * An interface with methods that can be overridden
- * in the internal [LinearLayoutManager].
+ * Helper class with properties that match the methods that can
+ * be overridden in the internal [LinearLayoutManager]. This is
+ * an abstract class instead of an interface so we can have
+ * default values for properties as we need to call `super`
+ * for properties that are not provided (null).
  */
-public interface LayoutHelper {
+public abstract class LayoutHelper {
     /**
      * Calculates the amount of extra space (in pixels) that should be laid out by
      * [CalendarLayoutManager] and stores the result in [extraLayoutSpace].
@@ -18,5 +21,5 @@ public interface LayoutHelper {
      *
      * @see [LinearLayoutManager.calculateExtraLayoutSpace]
      */
-    public fun calculateExtraLayoutSpace(state: RecyclerView.State, extraLayoutSpace: IntArray) {}
+    public open val calculateExtraLayoutSpace: ((state: RecyclerView.State, extraLayoutSpace: IntArray) -> Unit)? = null
 }
diff --git a/view/src/main/java/com/kizitonwose/calendar/view/WeekCalendarView.kt b/view/src/main/java/com/kizitonwose/calendar/view/WeekCalendarView.kt
@@ -151,7 +151,7 @@ public open class WeekCalendarView : RecyclerView {
         }
 
     /**
-     * Interface with methods that can be overridden
+     * Helper class with methods that can be overridden
      * in the internal layout manager.
      */
     public var layoutHelper: LayoutHelper? = null

diff --git a/view/src/main/java/com/kizitonwose/calendar/view/YearCalendarView.kt b/view/src/main/java/com/kizitonwose/calendar/view/YearCalendarView.kt
@@ -327,7 +327,7 @@ public open class YearCalendarView : RecyclerView {
         }
 
     /**
-     * Interface with methods that can be overridden
+     * Helper class with methods that can be overridden
      * in the internal layout manager.
      */
     public var layoutHelper: LayoutHelper? = null

diff --git a/view/src/main/java/com/kizitonwose/calendar/view/internal/CalendarLayoutManager.kt b/view/src/main/java/com/kizitonwose/calendar/view/internal/CalendarLayoutManager.kt
@@ -73,13 +73,9 @@ internal abstract class CalendarLayoutManager<IndexData, DayData>(
     }
 
     override fun calculateExtraLayoutSpace(state: RecyclerView.State, extraLayoutSpace: IntArray) {
-        val layoutHelper = getLayoutHelper()
-        if (layoutHelper != null) {
-            layoutHelper.calculateExtraLayoutSpace(state, extraLayoutSpace)
-            // If the interface is provided but the method is not overridden.
-            if (extraLayoutSpace.isEmpty()) {
-                super.calculateExtraLayoutSpace(state, extraLayoutSpace)
-            }
+        val calculateExtraLayoutSpace = getLayoutHelper()?.calculateExtraLayoutSpace
+        if (calculateExtraLayoutSpace != null) {
+            calculateExtraLayoutSpace(state, extraLayoutSpace)
         } else {
             super.calculateExtraLayoutSpace(state, extraLayoutSpace)
         }